The role of vitamin D3 in ameliorating LPS-induced flesh quality depress in grass carp (Ctenopharyngodon idella): Insights into antioxidant capacity, collagen synthesis, and myofiber development

Abstract

The global aquaculture industry struggles to maintain flesh quality under stress conditions, particularly during pathogen infections. This study investigated the effects of dietary vitamin D₃ (VD₃) supplementation on flesh quality and myofiber development in on-growing grass carp (Ctenopharyngodon idella) subjected to lipopolysaccharide (LPS)-induced stress. A 70-day feeding trial was conducted with two dietary treatments (control group and VD₃ group), followed by an LPS challenge. Results demonstrated that VD₃ significantly mitigated LPS-induced deterioration in flesh quality by enhancing crude protein and lipid content, reducing moisture levels, and improving pH, and hydroxyproline. VD₃ enhanced collagen synthesis via TGF-β/Smads signaling pathway and attenuated oxidative damage by reducing oxidate damage biomarkers, while boosting antioxidant enzyme activities (SOD, CAT, GR, GPx, and GST) and glutathione content. Moreover, VD₃ alleviated endoplasmic reticulum stress by downregulating key markers (ATF6, PERK, eIF2α, XBP1, CHOP, IRE1, and GRP78). Furthermore, VD₃ promoted myofiber hypertrophy, as indicated by upregulating cell cyclins (Cyclin B, Cyclin D, and Cyclin E), PCNA, and cell adhesions (Cadherin-1, Cadherin-17, Cadherin-18, Integrin α10, Integrin β1, and Integrin β2). These findings indicate that VD₃ improves flesh quality through the augmentation of antioxidant capacities, collagen synthesis, and myofiber development, while mitigating LPS-induced oxidative and endoplasmic reticulum stress. This research offers novel perspectives into VD₃ as a nutritional intervention for enhancing stress resilience and flesh quality in aquaculture.